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Biomedical subjects

R Ruiz

Publications and source records attributed to R Ruiz.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Hemorrhagic and edema-forming activity and histologic changes in the mouse footpad induced by venoms from Argentinian Bothrops and Crotalus genuses].

Hemorrhagic, oedema-forming activities and histopathological alterations in the mouse footpad induced by Bothrops and Crotalus snake venoms from Argentina. Hemorrhagic and oedema-forming activities of various Bothrops and Crotalus snake venoms from Argentina were studied, together with histological alterations in the mouse footpad. The highest oedema-forming activity was found in the venom of B. jararaca, followed by B. jararacussu, B. neuwiedii diporus, B. alternatus, and Crotalus durissus terrificus. Regarding hemorrhage, the highest activity was found in the venom of B. neuwiedii diporus, followed by B. jararacussu, B. alternatus, and B. jararaca. No hemorrhage was observed after injection of Crotalus durissus terrificus venom, in agreement with histological observations of injected footpads. Histological analysis revealed a conspicuous inflammatory reaction in the injected footpad, characterized by oedema and an inflammatory infiltrate rich in polymorphonuclear leucocytes. Necrotic blood vessels and dilated lymphatic vessels were observed after injection of B. jararaca and B. jararacussu venoms, and myonecrosis was evident in tissue of mice injected with B. alternatus and B. neuwiedii diporus.

Animals↗
PubMed1998

Alfentanil decreases the excitatory phenomena of sodium methohexital.

STUDY OBJECTIVE: To evaluate the effects of alfentanil or lidocaine on the excitatory phenomena (myoclonus, cough, hiccough) caused by methohexital anesthesia and on the hemodynamic changes induced by retrobulbar block. DESIGN: Prospective, randomized, placebo-controlled, double-blind study. SETTING: University-affiliated, tertiary-care hospital. PATIENTS: 60 ASA physical status II and III patients who were admitted for elective cataract extractions and intraocular lens implantations. INTERVENTIONS: Patients were randomly assigned to one of three groups. After adequate preoxygenation in the holding area, Group 1 received alfentanil 5 micrograms/kg intravenously (i.v.), Group 2 received lidocaine 1 mg/kg i.v. and Group 3 received the placebo (saline) i.v. Immediately after the bolus injection of the study solution, sodium methohexital 1.5 mg/kg was injected i.v. over 30 seconds. As soon as the eyelid reflex was lost, the retrobulbar block was placed over 5 seconds. MEASUREMENTS AND MAIN RESULTS: Occurrences of excitatory phenomena were recorded by an independent observer who was blinded as to treatment allocation. Other side effects such as oculocardiac reflex, nausea, vomiting, itching, or chest wall rigidity were recorded. Vital signs were recorded at baseline and 1, 3, and 5 minutes after placement of the block. In the alfentanil group, the incidence of myoclonus or cough was significantly less than in the lidocaine or placebo groups. Alfentanil also decreased systolic and diastolic blood pressure significantly at 1, 3, and 5 minutes after retrobulbar block. Changes in heart rate were not significantly different from baseline. CONCLUSION: A small dose of alfentanil (5 micrograms/kg i.v.) decreases myoclonus and cough induced by sodium methohexital anesthesia i.v., resulting in improved quality of induction of anesthesia. Alfentanil also attenuates the cardiovascular responses caused by placement of a retrobulbar block.

Adult↗
PubMed1998

Safety profile of WinRho anti-D.

WinRho anti-D is manufactured with multiple processes to minimize the risk of transmitting blood-borne diseases such as viruses. These safety features include donor selection, plasma testing, solvent-detergent viral inactivation, and nanofiltration. To date, there has not been any case of viral transmission in association with use of WinRho anti-D. Adverse drug reactions are infrequent and generally mild; the most common are headache, fever, and chills. Some degree of hemolysis is inevitable due to the mechanism of action of WinRho anti-D, but this is predictable and transient. A few cases of intravascular hemolysis have been reported; hypersensitivity reactions are very rare. WinRho anti-D has been shown in both clinical trials and postmarketing surveillance to be safe and effective in the treatment of idiopathic thrombocytopenic purpura (ITP) and in the prevention of Rh isoimmunization.

Drug Hypersensitivity↗
PubMed1998

[Hernia of the lumbar discs in persons at work. Results of a retrospective study in a series of 189 consecutive patients].

INTRODUCTION: Owing to recent advances in the diagnosis and treatment of lumbar disc pathology, the functional results obtained have improved, although there are still certain factors which affect this. The results in the work place are particularly problematic. OBJECTIVE: With the aim of finding an answer to the problem of relapse of the sciatica syndrome in patients operated on for hernia of the lumbar discs, we describe a study carried out in a consecutive group of patients who had had operations for hernias of lumbar discs whilst at work, within the context of revindication involved in this situation. PATIENTS AND METHODS: We describe the results obtained in a series of 189 patients who had been operated on for lumbar disc pathology. Conventional open surgery was performed in 105 cases. Percutaneous nucleotomy was done in the remainder. In 17.39%, operations were done at more than one level, making a total of 265 discs operated on. RESULTS: These were considered good when the patient returned to his former work. Good results were obtained in 72% of the patients treated by open surgery and 68% of those treated by percutaneous nucleotomy. The re-operation rate was 8.57% for open surgery and 32.14% for percutaneous nucleotomy (p < 0.05). CONCLUSIONS: The main reason for re-operation was a recurrence of disc protrusion. Good results were obtained in 80% of those reoperated. All reoperations were done using open surgery techniques. Overall assessment of the cases, including initial and re-operations, gave good results, reaching 83.59% in the current series.

Adult↗
PubMed1997

SUTIL: intelligent ischemia monitoring system.

SUTIL is an intelligent monitoring system for intensive and exhaustive follow up of patients in coronary care units. This system processes electrocardiographic and hemodynamic signals in real time, with the main objective of detecting ischemic episodes. In this paper, we describe the tasks included in SUTIL. In addition to basic tasks, those at higher levels will also be presented. Some of these latter tasks attempt to mimic, to some extent, the way in which the human expert operates.

Algorithms↗
PubMed1997

Adaptation drift suppression in blood glucose self-tuning control.

To improve the glycemic regulation in clamping, a modification of the recursive least squares (RLS) estimation to be applied to any self-tuning adaptive control algorithm has been developed. It has been used in combination with a pole assignment controller, and its results have been compared through computer simulation in 12 test models with 3 other algorithms. It produces an improvement in the efficiency and the control cost, and it shows indications of ameliorating the stability. It also has been observed that for glycemic control, a minimum variance controller (control advance moving average controller [CAMAC]) is very efficient, whereas an empirical type of controller (Clemens) requires low control action. Some recommendations are made for the use of the algorithm in clamping in a hypothetical electromechanical endocrine artificial pancreas.

Algorithms↗
PubMed1997

[Hemorrhage induced by snake venoms in Argentina].

Mice of 18 and 20 g were injected intradermally with 0.1 ml of serial dilution of venom in saline solution 0.9 buffered pH 7.2. Groups of 4 animal were formed, they were sacrificed 2 hours after inoculation. Skin of every mouse was put out, and the haemorrhagic area was measured Bothrops alternatus, Bothrops jararaca, Bothrops jararacussu and bothrops neuwiedii venoms were used. Crotalus durissus terrificus did not show any haemorrhagic activity.

Animals↗
PubMed1996

[Relationship between blood levels of sex hormone binding globulin, testosterone levels in blood and saliva and body morphology in premenopausal women].

BACKGROUND: The concentrations of the globulin binding of sexual hormones (GBSH) and serum and saliva testosterone were studied, as well as the free testosterone index (FTI), in a group of 75 premenopausic women of 42 years of age. These concentrations were correlated with the body mass index (BMI) and the relationship between the waist and hip perimeters (WHI) as an index of body fat distribution. MATERIAL AND METHODS: Anthropometric measurements were performed in all the women studied. The BMI was used to classify the women as obese or not obese, while the WHI was used to classify fat distribution as android or gynoid type. The hormone determinations were carried out by radioimmunoassay and the GBSH by fluorescence immunoassay. RESULTS: A significant positive correlation was observed between FTI and BMI (p = 0.024) and a negative correlation was seen between GBSH and WHI (p = 0.024). A significant decrease was found in the GBSH levels in obese women with respect to those who were not obese (p = 0.025) and between those with android fat distribution versus gynoid fat distribution (p = 0.032). CONCLUSIONS: The modifications observed in the concentrations of the globulin binding sexual hormone in obese premenopausic women and the absence of the same in the free testosterone indexes may be explained because of other steroids such as androstenodiol and dehydrotestosterone are elevated. The measurement of globulin binding sexual hormone concentrations may be an early marker of alteration in the androgenic status in obese women.

Adult↗
PubMed1996

[Survival in patients with sick sinus syndrome and artificial pacemaker. Determining clinical factors].

INTRODUCTION AND OBJECTIVE: The hypothesis that ventricular pacing is the most important factor in the survival of patients with Sick Sinus Syndrome remains controversial. The aim of this report was to determine independent clinical variables to predict survival in paced SSS patients. METHODS: Retrospective, nonrandomized study of 153 patients with a mean age of 69 +/- 11 years, who received an initial pacemaker for Sick Sinus Syndrome between 1980 and 1994: 65 physiologic pacing (32 dual chamber, 33 atrial) and 88 ventricular pacing mode. After a maximum follow up of 177 months (median 57 months) the end point was total mortality. RESULTS: Total mortality was 21%. Using univariate analysis, single chamber ventricular pacing, age > or = 70 years and NYHA > or = 2, was associated with a higher risk for total mortality (4 times increased risk for ventricular pacing compared to other pacing modalities). Independent predictors using multivariate analysis were: 1) NYHA > or = 2 (p < 0.05). 2) Coronary artery disease (p < 0.01). 3) Chronic obstructive pulmonary disease (p < 0.05) and 4) Gender (p < 0.05). CONCLUSIONS: Mortality in patients with the Sick Sinus Syndrome is strongly predicted by preimplant baseline clinical variables. Our data indicate that the role of ventricular pacing mode remains inconclusive. A large, randomized study is necessary to confirm these results.

Age Factors↗
PubMed1995

Community-based assessment of safety and immunogenicity of the whole cell plus recombinant B subunit (WC/rBS) oral cholera vaccine in Peru.

Every year since its introduction in 1991, there have been epidemics of cholera in Lima, Peru. Vaccination is one approach to the control of cholera. A pilot study was conducted to assess the safety and immunogenicity of a whole cell plus recombinant B subunit (WC/rBS) cholrea vaccine in Lima, Peru. Five hundred and forty-one volunteers aged 2-65 years received two doses two weeks apart of WC/rBS vaccine or Escherichia coli K12 placebo administered in bicarbonate buffered water. Symptoms were monitored on all subjects and blood was collected from 102 persons before the first dose and two weeks after the second dose. Mild post-vaccination gastrointestinal symptoms were reported with equal frequency for both the vaccine and placebo recipients. Among 51 vaccines, 49% had a twofold or greater increase in serum vibriocidal titers (GMT = 78; range < 1:10 to 1:5120); and 92% and 82% developed a twofold or greater serum anti-cholera toxin IgG and IgA response, respectively. Persons with elevated prevaccination vibriocidal titers had a decreased response to the WC/rBS. Age and blood group did not affect the immune response. The WC/rBS vaccine was safe and immunogenic in a group of native Peruvians.

Administration, Oral↗
PubMed1995

Efficacy and tolerability of ciprofloxacin prophylaxis in adult household contacts of patients with cholera.

We conducted a randomized double-blinded study in Lima, Peru, to assess the tolerability and efficacy of a single 250-mg dose of ciprofloxacin in preventing diarrhea and Vibrio cholerae O1 infection among household contacts of bacteriologically confirmed index cases. Adult household contacts with negative baseline stool cultures were included. A total of 213 household contacts were evaluable. The study drugs were well tolerated in both groups. Ciprofloxacin did not prevent the acquisition of V. cholerae O1 infection nor the development of diarrhea. However, in a subgroup of 30 household contacts with positive baseline stool cultures a reduction in the bacterial load and a trend toward prevention of diarrhea were observed among ciprofloxacin recipients. When all household contacts were evaluated, a trend toward prevention of diarrhea was observed with the prophylactic regimen. Ciprofloxacin failed to prevent V. cholerae O1 infections during a period of low transmissibility.

Administration, Oral↗
PubMed1995

Ciprofloxacin for the treatment of cholera: a randomized, double-blind, controlled clinical trial of a single daily dose in Peruvian adults.

We conducted a randomized, double-blind clinical trial to compare ciprofloxacin (250 mg once a day for 3 days) with tetracycline (500 mg four times a day for 3 days) in terms of efficacy and safety in the treatment of moderate-to-severe cholera in Peruvian adults. The baseline characteristics of the groups were similar. A total of 202 patients (102 in the tetracycline group and 100 in the ciprofloxacin group) were included in the efficacy analysis. The clinical and bacteriologic efficacies of the two regimens were similar. The study drugs were well tolerated. We conclude that ciprofloxacin given once a day is as effective as the standard tetracycline regimen for the treatment of cholera in adults. The ciprofloxacin regimen may represent an alternative to the standard treatment in areas where Vibrio cholerae O1 strains that are resistant to commonly used antimicrobials are prevalent.

Administration, Oral↗
PubMed1995

Continuous heart rate variability monitoring through complex demodulation implemented with the fast Fourier transform and its inverse.

UNLABELLED: A new method for the analysis of 24-hour heart rate variability (HRV) using complex demodulation (CDM) implemented with the fast Fourier transform (FFT) and its inverse is described. In a control group with palpitations and dizzy spells (n = 30, 47.2 +/- 16.7 years) the relationship between HRV parameters and subject age was investigated. CDM was used to obtain the amplitude and frequency of the low frequency (LF) and high frequency (HF) oscillations for 8 diurnal hours and 4 nocturnal hours. Differences between the two periods were seen in the LF/HF ratio (2.2 +/- 0.6 vs 1.5 +/- 0.6; P < 0.0001), HF amplitudes (12 +/- 6 vs 17 +/- 7 normalized units, P < 0.05), and in the mean frequency of the LF oscillations (0.078 +/- 0.008 vs 0.073 +/- 0.007 Hz, P < 0.01). During the daytime, age was inversely correlated to HF amplitude (r = -0.60), directly correlated to HF mean central frequency (r = 0.40), inversely correlated to LF amplitude (r = -0.55), and likewise inversely correlated to LF mean central frequency (r = -0.74, P < 0.001). At night, age was only inversely correlated to HF amplitude and to LF mean central frequency. CONCLUSIONS: Continuous HRV monitoring through CDM implemented with the FFT and its inverse differentiates the periods of diurnal activity and nocturnal rest as an expression of two different activity states of the autonomic nervous system. It allows nonstationary analysis, and separately provides mean and instantaneous oscillation amplitude and frequency. Subject age is not equally related to mean amplitude and frequency of a given oscillation.

Adolescent↗
PubMed1995

Evaluation of an immunoturbidimetric assay of serum digoxin without sample pretreatment.

We have evaluated a new turbidimetric immunoassay test (On Line, Roche) for the quantification of digoxin in human serum without sample pretreatment. The assay, automated on a Cobas-Mira clinical analyser, is based on the measurement of the changes in absorbance that occur when digoxin-coated microparticles aggregate with digoxin antibody; the aggregation reaction is partially inhibited by digoxin in the sample. The calibration curve extends up to 6.4 nmol/l, with a wide measuring range, and was stable at least for 10 days during the studied period. The intra- and inter-assay coefficients of variation were in all cases lower than 7%. The detection limit of the assay was 0.256 nmol/l and the linearity, assessed by measuring serial dilutions of poisoned patient sera, showed correlation coefficients higher than 0.998. There is no interference from bilirubin (up to 340 mumol/l) or haemoglobin (up to 7900 mg/l), although a positive interference by lipids was found, which can be avoided by previous delipidation of these sera. No digoxin-like factors were identified affecting digoxin values in a concentration higher than that of the sensitivity of the assay in samples of premature infants, pregnant women, or patients with renal or hepatic failure. Correlation coefficients between the turbidimetric assay and two immunoassays (fluorescence polarization and RIA) were 0.983 and 0.955 respectively, calculated from the assay of 102 and 98 samples. Nevertheless the values obtained by the evaluated assay were proportionally 20% higher, a fact probably related to differences in calibrators.

Bilirubin↗